Conformable pad filled with elastomeric particles

ABSTRACT

A PAD WHICH WILL CONFORM TO IRREGULAR OBJECTS, SUCH AS PORTIONS OF THE HUMAN BODY, RELATIVELY QUICKLY AND WHICH IS FILLED WITH ELASTOMERIC PARTICLES COATED WITH A THIN LAYER OF A LUBRICANT. THE ELASTOMERIC PARTICLES ARE PREFERABLY IN THE RANGE OF 1/16-1/4 INCH IN MAJOR DIMENSION AND UPON LOAD APPLICATION FLOW READILY AT FIRST AND LATER ACT MUCH LIKE AN OPEN CELL FOAM MATERIAL AS THE PARTICLES   REDISTRIBUTE BETWEEN THE PADDED SURFACE AND THE SUPPORTING SURFACE TOWARD A UNIFORM LOAD DISTRIBUTION.

YCONFORMABLE PAD FILLED WITH ELAS'IOMERIC PARTICLES Filed D80. 30, 1968R. W. WIELE Jan. 5, 1971 2 Sheets-Sheet 1 Q INVENTOR. .Rnzrl W M's/eCONFORMABLE PAD FILLED WITH ELASTOMERIC PARTICLES Filed Dec. 30, 1968 R.W. WIELE Jan. 5, 1971 2 Sheets-Sheet 2 INVENTOR. 215m 1% mu nited StatesPatent 3,552,044 CONFORMABLE PAD FILLED WITH ELASTOMERIC PARTICLESRobert W. Wiele, Minneapolis, Minn., assignor, by mesne assignments, toSports Technology, Inc., Eden Prairie,

as portions of the human body, relatively quickly and which is filledwith elastomeric particles coated \with a thin layer of a lubricant. Theelastomeric particles are preferably in the range of inch in majordimension and upon load application flow readily at first and later actmuch like an open cell foam material as the particles redistributebetween the padded surface and the supporting surface toward a uniformload distribution.

CROSS REFERENCE TO RELATED APPLICATION This application is acontinuation-in-part of my copending application Ser. No. 695,167, filedJan. 2, 1968, and now abandoned, for Conformable Pad Filled WithElastomeric Particles.

BACKGROUND OF THE INVENTION (1) Field of the invention The inventionrelates to pads that conform to irregular shapes.

(2) Prior art A first type of conformable pad is shown in Pat. No.3,325,920 which shows a material which conforms to a shape from repeatedworking relatively slowly but will retain the shape when the load isremoved. A quickly conformable pad is shown in US. Pat. No. 3,374,561.

The slowly conforming material of Pat. No. 3,325,920 does not flowquickly enough for certain applications where high, rapidly changingloads are encountered. The use of liquid pads for quick conformabilityhas been found to have some difliculties in manufacturing of the liquidtight covering for the pads. The need for a quickly conformable paddingmaterial which gives adequate support during usual skiing loads, inparticular, and which will then also quickly conform or flow under highloads to redistribute loads has been recognized.

SUMMARY OF THE INVENTION The present invention relates to the use ofelastomeric pellets or particles of sizes usually about to inch in majordimension covered with a very thin coating of lubricant so that theywill slide past each other relatively easily and enclosed within aclosed container having flexible, but essentially non-distensible wallsto obtain a quickly conformable pad that is very economical to make.

DESCRIPTION OF THE DRAWINGS 3,552,044 Patented Jan. 5., 1971 DESCRIPTIONOF THE PREFERRED EMBODIMENT Referring to FIG. 1, a ski boot 10 is shownfragmentarily to give a proper setting for the usage of the pad. Theboot has a lower portion 11 with lining pads 12 at the front part of theboot and pads 12A at the rear of the boot (about from behind the anklebone rearrwardly) and an articulated ankle cufl section 13 which ispivoted with members 14 to the lower part of the boot. As shown, theankle cuff section is lined with pads 15 made according to the presentinvention. The pads 15 are made so that they have a backing pocket intowhich pillows 16 are inserted for backing up the pads 15 so they fitclosely to the leg of the wearer. The pockets have suitable openingsinto which the pillows can be inserted. The boot has a side flap whichopens to let the foot be inserted into the boot, and a pair ofencircling cables 17, 117 attached to a cover 18 used for holding thedoor in closed position. The boot construction is shown in US. Pat. No.3,374,561 and also shown is a more detailed showing of the normal padconfiguration.

The pads 15 as shown in FIG. 2, comprise an outer covering 21 of astrong cloth cut into the desired outer configuration and filled with amaterial indicated at 22 comprising discrete or individual particles orpellets 23 of elastomeric material. The pellets of elastomeric materialare each uniformly coated very thinly with a lubricant material. Thecoating is shown in shading only in the drawings because it is a verything coating, but does cover the entire surface of each pellet thinly.The material pellets 23 substantially fill the bag and then the bag issealed by stitching or other techniques of closing so it is a sealedunit. The pellets 23 substantially fill the bag, so that as the pellets23 move under pressure, they deform or change the shape of the bag orouter covering 21 in another area.

Thus, the cloth or the covering 21 and the stitching or sealing membershave to have a tensile strength high enough to withstand the in useloads tending to burst the bag when loads are applied to the bag itself.Desirably, the cloth should be coated with a material that is notadversely atfected by grease and which prevents the grease or lubricantcoating the particles 23 from wicking through the cloth. The lubricantis preferably a silicone base type grease or oil. Dow Corning No. 7silicone grease has proved satisfactory. The elastomeric members used inone example were made from rod material supplied by the Shell ChemicalCorporation and sold under the trademark Thermolastic having a durometerreading of about 45 Shore A (Type 226 Thermolastic material was used).Thermolastic is a butadiene-styrene copolymer. The pellets used wereabout A; of an inch in diameter and random length, but usually about M;of an inch long, forming small cylinders that had substantially equaldimensions in all directions, which is important for good flowproperties. The softer durometer material rods are usually slightlylonger ranging up to inch long. In mixing, only enough of the siliconegrease to thinly coat each pellet was used. Cylinders were used in thisapplication because of their availability, low cost and their success intesting.

The cloth cover used was a Hypalon-coated nylon cloth. In use, the padgives adequate support without harsh feel within the ski boot cuff, andWhen subjected to high loads, from the leg of a boot wearer, theparticles 23, being relatively large and having the coefiicient of thefriction between the pellets reduced with the lubricant, will flow ormove out of the way of the highest load areas and conform more generallyto the shape of the leg in the high load carrying areas, such as aroundthe configuration of the front portions of the leg bone when a forwardload is encountered, or around the side portions of the leg bone when aside load, such as when edging a ski is encountered. The pellets orparticles 23 initially flow or redistribute relatively readily underthis load, and then cease to flow when the loads are quite evenlydistributed. The bag or cover restrains the pellets from furtherflowing. At this point, the material acts like an open celled rubberfoam. The elastomeric pellets compress and deform into the interstitialspaces between the pellets. The pad then has force-displacementcharacteristics almost wholly dependent on the shapes of the pellets andtheir modulus of elasticity. When being displaced easily, the pelletswill deform slightly as well to make them slip past each other readily.These elastomeric pellets then give a cushioning effect even after theyhave stopped flowing or moving when very high loads are encountered onthe leg and this adds to the comfort of the leg in the cuff area of theski boot where high loads are encountered. The pad will still conform togive comfort and snug fit when under lower loads. When the high loadsare removed, the forces on the pellets are then redistributed as theywere initially, since the pellets flow or move within the sealed bagback to their initial position supporting the leg in a normal manner.

The rubber or elastomeric pellets have a durometer range that ispreferably between 35 Shore A and 65 Shore A for use in the ski bootapplication described. However, the total range can be from about 4Shore A up to 95 Shore A depending on the loads encountered and thephysical dimension of the particles and pads. The pellets areelastomeric material and must have the ability to withstand thelubricant being used. Any combination of lubricants can be made and evena dry lubricant can be used.

The pellets can be natural rubber, urethane rubber or other syntheticelastomers.

Ratios normally used for mixing of the pellets by volume include a 240to 1 ratio (240 parts of the pellets to 1 part of the lubricant), or byweight a 150 to 1 ratio, using the Type 226 Thermolastic pellets and theDow Corning 7 silicone grease. The pellet volume given is the freeflowing bulk volume which may be measured by pouring a quantity into acontainer of known volume. The ratio can range from approximately 120 to1 up to 480 to 1 by volume (the pellets representing the larger volume).

The pads 12 and 12A are constructed similar to pad 15 just described.They have outer covers and are filled with elastomeric particles havinga thin liquid or lubricant coating. As described subsequently, thepellets in each set of pads 15, 12 or 12A can differ in durometer toachieve different holding properties.

A second pad is shown in FIG. 3, this again has an outer covering 26made of a strong material and sewed along its edges 27 to be sealed. Theinterior of the pad here is shown with spherical elastomeric pellets 28.The spheres can be of uniform size or varying size and will also flow ormove quickly out of the way when subjected to load, much like thecylinders previously described. The pellets 28 are made of any suitableelastomeric material. Once the flowing of the pellets has stopped, thematerial takes on the qualities of and becomes much like an open celledfoam. The pellets individually will compress and thus will give highsupport characteristics without discomfort.

The material can be used for medical seat cushions or other areas wherequick conformability is desired, such as shoe pads, ear defenders (noisesuppressors) and the like.

The present pad does not rely on a liquid for quick conformability underhigh rapidly changing load thereby eliminating the problems encounteredin containing a liquid in a pad. The filler material is low cost, and itwill flow quickly when the particle size for the ski boot example isover V of an inch and up to A1, inch and the preferred range of particlesize about /a of an inch major dimension. The dimensions of theparticles .are substantially equal in all directions. When the materialstops flowing the material will act like an open celled foam to give acushioning effect and not flow completely out of the way of the highload applying object.

In boot applications, the cuffs can be padded with pads having pelletsabout Shore A durometer hardness, the pads in the instep and frontportion of the foot about Shore A durometer hardness, and in the heelportion of the foot Shore A durometer hardness, to give good holdingaction. The pellet pads enhance skiing because of rapid conformability,and the firmness of the pad can be varied for the individual portion ofthe boot. Soft particles are used in the cuff where rapidly changingloads are encountered; medium hardness around the instep and front ofthe foot for a balance of comfort and good control and firm particles(65 durometer) around the heel where the pads should not compressgreatly. The sides of the foot in the heel area are held firmly for goodcontrol. The durometer of the pellets can thus be easily changed to fitconditions.

The pads 12 and 12A can be compartmented to prevent excessive movementof the material and extend to fully support and hold a foot in the boot.

The back up pillows or pads 16 are used for fitting the boots properlyand can be filled with material such as that disclosed in US. Pat. No.3,325,920 or can be filled with pellets just as pads 15 or 25. If theback up pads 16 are filled with pellets, the firmness of the overall padsystem can be varied by having a different durometer pellet in the backup pad 16 from the pad it is backing up. Back up pads 16 are used toback up pads 12 and 12A to obtain good fit too.

The heel portion of the foot refers generally to the part of the footbelow and generally to the rear of a transverse vertical plane passingthrough the ankle bone. This part of the foot is held down for goodcontrol of skis. The front portion of the foot means the part generallyahead of the angle bone.

The elastomeric particle pads have an advantage in that the durometer ofthe particles can be selected to suit individual usages.

Referring specifically to FIG. 4, a football helmet 30 is shown. Thehelmet has a liner member 31 which can be suitably fastened in place,with snaps as shown, and the liner member 31 comprises a double wall padthat can be compartmented, and is filled with the pellets 32 ofelastomeric material covered with a very thin coating of the oil, in theratios previously given. The pellets 32 would be of a durometer in therange of 45 Shore A, and these pellets will give .a very good impactresisting cushion to the head, and also will conform very quickly toirregularities of the head. Back up pads again can be used for getting agood fit.

If desired, the pads around the ears as indicated at 33 can be filledwith pellets that are softer or smaller size to give better comfort. Therange here may be around 35 Shore A hardness. The pads can be made sothat they can be backed up (other pads inserted) with other pads, ifdesired, to change the fit of the helmet.

In FIG. 5, an ear defender or protector 37 is shown. This comprises acup shaped member fastened to a head cross band 38 (there are two cups,one for each ear) which is used for deadening sounds. A cushion member39 surrounds the openings of the cup shaped member. The cushion member39 is filled with pellets 40 made of an elastomeric material thinlycoated with oil or grease as previously described to provideconformability around the ear and to insure that the sound is adequatelydeadened. The elastomeric particles used are soft enough to give acushion here as well, and would range in the area of 3545 Shore Adurometer reading. The pellets 40 conform quickly to the irregularitiesof the head and provide a cushion. The conformability insures that thecushion will seal around the ear to deaden all noises and will notbecome uncomfortable after wearing the defender for a substantial lengthof time. The elastomeric material provides an adequate cushion toprevent discomfort.

With the larger elastomeric particles, ranging from inch up to A1 of .aninch, and averaging about /8 of an inch in major dimension theconformability characteristics are enhanced substantially because thelarger particles will slide past each other easily. The particles alsowill crush or conform under load to prevent any sharp edges from digginginto the skin of the wearer. The amount of liquid material, of course,is kept to a minimum and is well below the volume of the void spacesbetween the particles. The lubricant merely insures that the particleswill slip easily by each other to provide a conforming action, and theparticles will merely compress if further loaded.

What is claimed is:

1. A pad comprising an outer container substantially filled withmaterial consisting of discrete elastomeric particles having a thincoating of lubricant material on the surface of each particle comprisinga mixture of a lubricant material and particles in a ratio between 120to 1 and 480 to 1 by volume, where the 1 represents the lubricantmaterial.

2. A pad according to claim 1 wherein the elastomeric particles arecylindrical.

3. A pad according to claim 1 wherein the elastomeric particles arespherical.

4. The pad specified in claim 1 wherein the lubricant material is agrease.

5. A pad comprising an outer container substantially filled with amaterial consisting of discrete elastomeric particles having a durometerin the range between 35 and 65 Shore A and having a thin coating oflubricant material on the surface of each particle.

6. The pad of claim 5 wherein the particles have substantially uniformdimensions in all directions.

7. A pad comprising an outer container substantially filled withmaterial consisting of discrete elastomeric particles having a durometerin the range between 4 and Shore A and having a thin coating oflubricant material on the surface of each particle.

8. The pad of claim 7 wherein the lubricant material is a grease.

9. The pad of claim 7 wherein the material substantially filling saidpad is made by mixing a lubricant material and elastomeric particles ina ratio between to 1 and 480 to 1 by volume, where the 1 represents thelubricant material.

10. The pad of claim 7 wherein the particles range in size between inchand 4 inch in major dimension.

11. The pad of claim 7 wherein the particles are larger than A inch inmajor dimension.

12. A pad for cushioning a portion of the human body against a hardouter member comprising a flexible, substantially non-stretchablecontainer of size and shape to cover the portion of the human body to bepadded, and a filling insert container consisting of discreteelastomeric particles ranging in size between inch and inch in majordimension, and a thin coating of a lubricant material on the surface ofeach particle.

13. The pad according to claim 12 wherein the particles range indurometer reading between 35 and 65 Shore A.

14. The pad of claim 12 wherein the discrete particles are comprised ofcylindrical members having a major dimension over inch.

References Cited UNITED STATES PATENTS 2,638,690 5/1953 Bullard 36-712,774,152 12/1956 Alber 36-71 3,325,920 6/1967 Werner et a1. 362.53,405,463 10/1968 Werner 362.5 3,374,561 3/1968 Werner et al. 362.5

PATRICK D. LAWSON, Primary Examiner US. Cl. X.R. 362.5

